Circle Vocabulary

Circle

The locus of points a given distance from a fixed point on a plane

Sphere

The locus of points a given distance from a fixed point in space

Radius

the line segment whose endpoints are the center and a point on the circle

Chord

the line segment joining any 2 points on a circle

Diameter

a chord that passes through the center of the circle

Secant

any line that has a subset that is a chord of the circle

Tangent

any line that intersects the circle at exactly one point

Great circle

the intersection of a sphere with a plane through its center

Concentric circles

have same center but different radii

Congruent Circles

circles with congruent radii

Central Angle

angle whose vertex is at the center of a circle

Inscribed Angle

angle whose vertex lies on the circle and whose sides have as chords of the circle

Inscribed Polygon

polygon whose verticles all line in the circle

Circumscribed Polygon

polygon whose sides are all tangent to the same circle

Arc

any part of a circle

Major Arc

greater than a semicircle(>180)

Minor Arc

less than semicircle(<180)